CHARACTERIZATION OF UPSTREAM MIXING CAVITIES AND A DOWNSTREA IBD

Sinopse

A key area of study in air-breathing hydrocarbon-fueled scramjet combustors is the characterization of cavity-based fuel injection and flame holding. One issue concerns oscillatory disturbances caused by trapped vortices in the main flame holder cavity as a fuel-air mixing enhancement technique. Previous research demonstrates that oscillatory disturbances can be carried downstream via the shear layer and alter the oscillatory characteristics of a downstream cavity. This study investigates the mixing effectiveness of three upstream direct-fueled mixing cavities as well as the effect on the oscillatory behavior of the downstream combustion cavity by the upstream mixing cavity. The three upstream mixing cavities are characterized in Mach 2 freestream flow with injection at three locations within each cavity. Non-intrusive visual data are collected using the nitric oxide (NO) Planar Laser Induced Fluorescence (PLIF) diagnostic technique to characterize mixing and shear layer influence. High frequency response pressure transducers measure pressure fluctuations in both the upstream and downstream cavities for comparative analysis. Injection at the upstream wall of the cavity provided greater penetration height into the freestream as well as faster mixing with the freestream compared to injection at the center or aft wall of the cavity. The pressure oscillations in each cavity showed strong similarities, however, the amplitudes of the frequencies were too small to be effective in lifting mass into the freestream.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.